BLASTOCLAD1ALES 685 



Sparrow (1932b: 291, pi. 7, fig. H; 1933c: 529), Emerson and Cantino 

 (1948); twigs, Sparrow and Barr (1955: 555), apples and twigs, Ziegler 

 and Linthicum (1957), United States; apples and ash twigs, H. E. 

 Petersen (1909: 395; 1910: 532, fig. 10), Lund (1934: 40, fig. 18), Spar- 

 row, Denmark; apple, Valkanov (1931a: 366), Bulgaria; twigs, Barnes 

 and Melville (1932:94), rose fruits, Cook and Forbes (1933:641), 

 Forbes (1935a: 237, pi. 10, fig. 10), twigs and apples, Sparrow (1936a: 

 455, pi. 20, fig. 5), tomato fruits, Blackwell (1937: 933; 1940: figs. 1-9), 

 Lloyd (1938: figs. 1-3), Emerson and Cantino (1948), Waterhouse 

 (1942), Great Britain; fruits of rose, banana, apples, Japonica, winter 

 cherry, Cotoneaster, Crooks (1937: 222, fig. 8), Australia; Pirus fruits, 

 Indoh (1940: 250, figs. 9 a-e), Japan; apples, Sparrow, Holland; to- 

 mato fruits, Shen and Siang (1948: 188), China; in soil, coll. Hansford, 

 Emerson and Cantino (1948), Uganda. 



The commonest species of the genus. Since the habit of the plant is 

 extremely variable, considerable observation on cultures derived from 

 single-spore strains growing on various twigs and fruits will be necessary 

 before the species can be adequately delimited. A glance at the figures 

 of what various authors consider this species will show that all plants 

 with somewhat cylindrical sporangia and resting spores which are thick- 

 walled and not beaked have been termed Blastocladiapringsheimii. Cer- 

 tain specimens showing more pronounced variations in thallus habit 

 have been segregated as distinct species (B. globosa, B. aspergilloides, B. 

 angusta, and so on). Attempts have also been made (Lloyd, 1938) to 

 arrange the thallus types in groups, the extremes being on the one hand 

 a globose type with a short cylindrical axis and on the other a slender 

 ramose type. Unfortunately, significant data can only be accumulated 

 by resort to single-spore cultures. Lloyd's observations over a period of 

 time on gross cultures of what was considered a single species showed 

 that there was no periodicity in the shape of the thallus, the frequency 

 of resting spores, or the presence or absence of setae. The lobed type 

 with definite cylindrical axis and the branched type with swollen apices 

 predominated. It is important to bear in mind that the latter type was 

 figured by Reinsch as typical of his species. 



The sizes given for the thallus are probably of very little significance. 

 Crooks (1937) has determined from a study of the size of the sporangia 



